1. Field of the Invention
The present invention relates to a method and sensor for detection of thermal history which are designed to examine for the deterioration in such specimens as exhaust gas purification catalysts, and inner walls in blast furnaces, boilers and incinerators.
2. Description of the Related Art
There has been disclosed in Japanese Patent Laid-open No. 212956/1994 a method of examining the automotive exhaust gas purification catalyst for deterioration. This method consists of monitoring cerium oxide CeO.sub.2 (constituting the catalyst) for its ability of oxygen storage and release by means of oxygen sensors placed at the inlet and outlet of the exhaust gas passage. The disadvantage of detection in this way is low sensitivity due to a very small change in the ability of oxygen storage and release of cerium oxide accompanied by catalyst deterioration. Another disadvantage is the necessity of using at least two oxygen sensors and comparing their outputs with reference values. Thus the above-mentioned technology needs a complex method and apparatus and is not satisfactory for the detection of catalyst deterioration.